On 7/1/08, Jon Smirl <[EMAIL PROTECTED]> wrote:
> On 7/1/08, Jean Delvare <[EMAIL PROTECTED]> wrote:
>
> > On Tue, 1 Jul 2008 13:00:08 -0400, Jon Smirl wrote:
> > > On 7/1/08, Grant Likely <[EMAIL PROTECTED]> wrote:
> >
> > > > My preference is for things like of_spi and of_i2c to go with the
> > > > related busses; I think it makes more sense to keep all the I2C stuff
> > > > together, but I've already lost that battle once.
> > >
> > > This is a similar problem to adding aliases to the i2c driver drivers
> > > for the device tree names of the i2c devices. Instead we have code in
> > > drivers/of/of_i2c.c that tries to guess the translation from device
> > > tree to linux names. Adding aliases to the drivers would eliminate the
> > > need for of_find_i2c_driver().
> > >
> > > I've previously posted patches implementing device tree names in the
> > > drivers that used ifdef to only instantiate on powerpc builds. For
> > > example....
> > >
> > > diff --git a/drivers/i2c/chips/tps65010.c b/drivers/i2c/chips/tps65010.c
> > > index e07274d..9cd1770 100644
> > > --- a/drivers/i2c/chips/tps65010.c
> > > +++ b/drivers/i2c/chips/tps65010.c
> > > @@ -571,6 +571,10 @@ static const struct i2c_device_id tps65010_id[] = {
> > > { "tps65011", TPS65011 },
> > > { "tps65012", TPS65012 },
> > > { "tps65013", TPS65013 },
> > > + OF_ID("ti,tps65010", TPS65010)
> > > + OF_ID("ti,tps65011", TPS65011)
> > > + OF_ID("ti,tps65012", TPS65012)
> > > + OF_ID("ti,tps65013", TPS65013)
> > > { },
> > > };
> > > MODULE_DEVICE_TABLE(i2c, tps65010_id);
> >
> >
> > Yeah, yeah, you've been asking for this for months already, but it's
> > just not going to happen, sorry. You want to abuse the standard Linux
> > alias mechanism for your personal (i.e. openfirmware) use, but that's
> > bad. Linux drivers shouldn't have to know whether they are used in
> > openfirmware trees and what device names are used there. And device
> > names as seen by user-space shouldn't vary depending on whether the
> > device comes from an openfirmware tree or not - otherwise all
> > user-space apps need to learn about both naming conversions.
> >
> > Unsurprisingly, no other subsystem does what you propose.
>
>
> Then what are all of the PCI aliases doing?
>
> The only difference is that you are recognizing the PCI group as a
> naming authority and not recognizing the PowerPC device tree group.
> But on the PowerPC platform that is our naming authority. That's why I
> proposed adding the names on ifdefs so that they disappear on non
> PowerPC platforms.
>
> PS - adding an alias to a driver does not change the name of the
> driver. My PCI e1000 module has about 100 aliases but it is always
> e1000.
Here's my e1000e sysfs entry:
[EMAIL PROTECTED]:/sys/bus/pci/devices/0000:00:19.0$ ls
broken_parity_status device local_cpus power resource2 uevent
bus driver modalias resource subsystem vendor
class enable msi_bus resource0 subsystem_device
config irq net:eth0 resource1 subsystem_vendor
[EMAIL PROTECTED]:/sys/bus/pci/devices/0000:00:19.0$ cat modalias
pci:v00008086d0000104Bsv00001028sd000001DBbc02sc00i00
>>>> This is the module alias that was used to load the driver.
[EMAIL PROTECTED]:/sys/bus/pci/devices/0000:00:19.0$ ls -l driver
lrwxrwxrwx 1 root root 0 2008-07-01 08:52 driver ->
../../../bus/pci/drivers/e1000e
>>>> The driver is always e1000e no matter which alias was used to load it.
>>>> "e1000e" is controled by the name field of the driver structure. That's
>>>> the publicly visible name for the driver.
>>>> Adding the OF aliases would change the modalias entry, not the driver
>>>> name.
The i2c implementation is adding a field to a device entry that
contains the driver name. No other device drivers I could find do
this.
[EMAIL PROTECTED]:/sys/bus/i2c/devices/1-0050$ ls
bus driver eeprom modalias name power subsystem uevent
[EMAIL PROTECTED]:/sys/bus/i2c/devices/1-0050$ cat name
eeprom
[EMAIL PROTECTED]:/sys/bus/i2c/devices/1-0050$ ls -l driver
lrwxrwxrwx 1 root root 0 2008-07-01 14:05 driver ->
../../../../bus/i2c/drivers/eeprom
[EMAIL PROTECTED]:/sys/bus/i2c/devices/1-0050$ cat modalias
[EMAIL PROTECTED]:/sys/bus/i2c/devices/1-0050$
I believe the correct way to get the driver name from sysfs is to
follow the driver link. The name field is probably legacy. Other
drivers in the system don't have a name entry on the device node.
Is the user space i2c code looking at the modalias entry?
--
Jon Smirl
[EMAIL PROTECTED]
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